The Importance of Drainage Planning in Property Development

Water is one of the biggest long-term risks to any building. Parts of Lagos are low-lying, rainfall can be heavy, and many areas have a high water table. Drainage that is planned late, or not at all, tends to be expensive to fix and can damage structures, finishes and access.

Start with how water moves across the site

Before design is fixed, understand where rainwater falls, where it naturally flows and where it can go. Levels matter. A building platform set too low, or a road that channels water towards a property, creates problems that no amount of later repair fully removes.

Plan the whole system, not just the pipes

• Surface drains and channels that collect run-off from roofs, paving and roads.
• Gradients that keep water moving instead of standing.
• Capacity to handle heavy rainfall, not average rainfall.
• A safe outfall or discharge point, agreed and available.
• Access points for inspection and cleaning.
• Separation of rainwater from foul drainage where required.

Estates need coordinated drainage

In an estate or multi-plot development, drainage in one plot affects its neighbours. A coordinated system, designed for the whole development, performs better than separate plot-by-plot solutions that push water onto each other.

Drainage and the building

Good drainage protects foundations, floors and walls. Poor drainage around a building contributes to damp, erosion of the ground beneath foundations, and damage to paving and external works. Waterproofing, floor levels and external falls should be designed together with the drainage.

Maintenance keeps it working

Drains block with silt, waste and vegetation. A planned routine of inspection and clearing, especially before the rainy season, keeps a system performing as designed.

Drainage is easiest and cheapest to get right at the design stage. Involving engineers early, and treating drainage as part of the core design, is one of the most practical ways to protect a property's value.